Crows are far from bird-brained and have been shown to use tools to solve complex problems that baffle five-year-old children.

Now researchers have revealed that, like humans, the birds store their tools when they don’t need them, sometimes even in 'toolboxes' so they can re-use helpful implements.

New Caledonian crows, which are famous for using stick tools to extract insects from tree holes and other hiding places, also keep their tools under their feet - especially when they are perched in treetops.

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Caw blimey! New Caledonian crows, which are famous for using stick tools to extract insects from tree holes and other hiding places, keep their tools under their feet (pictured) - when they are perched in the treetops

Several animals, including dolphins and chimpanzees use tools for foraging and some have been reported to re-use and transport them, but this is the first study to reveal what animals do with implements between meals.

Researchers at the University of St Andrews conducted experiments with wild-caught birds.

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The creatures hold tools in their bills when foraging, but need to put them down to eat.

‘We were really excited when we saw crows in our study site carefully placing tools under their feet, to use them again later,’ said Barbara Klump, lead author of the study, published in the Proceedings of the Royal Society.

The experts observed that crows look after their tools more carefully when foraging at height than on the ground. This crow s using a tool to poke at grubs hiding beneath tree bark

CROWS ARE AS INTELLIGENT AS CHILDREN

Crows have a reasoning ability rivalling that of a human seven-year-old, research has shown.

Scientists came to the conclusion after subjecting six wild New Caledonian crows to a battery of tests designed to challenge their understanding of cause and effect.

The tasks were all variations of the Aesop's fable, in which a thirsty crow drops stones to raise the level of water in a pitcher.

In the 'water displacement task', crows worked out how to catch floating food rewards by dropping heavy objects into water-filled tubes.

They demonstrated an ability to drop sinking rather than floating objects, solid rather than hollow objects, to choose a high water level tube over one with low water level, and a water-filled tube over one filled with sand.

The birds' understanding of the effects of volume displacement matched that of human children aged between five and seven, scientists from the University of Auckland claimed.

They observed that crows look after their tools more carefully when foraging at height than on the ground.

‘This makes perfect sense because the higher up you are, the more challenging it would be to recover a tool,’ she explained.

‘In fact, wild crows seem to get really upset when they accidentally drop their tools.’

Dr Christian Rutz, team leader and one of the study’s co-authors, said: ‘When you put a treasured pen in a pen holder, you know where it is, and can quickly find it again.

‘It turns out that crows do exactly the same, sometimes storing their tools in tree holes or behind bark.’

The crows were extremely good at keeping track of their tools, remembering where they had put them, and reusing them again to extract more meals shortly after.

This tool ‘safekeeping’ may be very important, as it means crows don’t have to repeatedly manufacture new tools and can spend more time on the critical business of finding food.

Exactly how long wild crows use individual tools for, and how far into the future they can plan, remains to be explored.

Safekeeping (pictured in this image) is important so crows don’t have to repeatedly manufacture new tools and can spend more time finding food

MUCH SMARTER THAN THE AVERAGE BIRD BRAIN

Members of the crow family are known to be among the cleverest of birds, but scientists are finding that they may have intelligence that rivals most mammals and even young children.

An experiment by the University of Cambridge showed that crows can perform tasks that three and four-year-old children have difficulty with.

Scientists said that, while having very different brain structures, both crows and primates use a combination of mental tools, including imagination and the anticipation of possible future events, to solve similar problems.

In a test set up by BBC Two, a crow called 007 completed an eight stage puzzle in two-and-a-half minutes (illustrated). It is one of the most complex tests of the animal mind ever devised

Other experiments involving the same family of birds found that Caledonian crows can use up to three tools in sequence to obtain food.

A study also found rooks can use stones to raise the level of water in a vessel in order to bring a floating worm into reach.

Urban-living carrion crows have been witnessed learning to use road traffic for cracking nuts.

The problem-solving creature performed the series of tasks without seeing the fiendishly difficult set up of the course beforehand.

The wild crow learned to use individual props during its three months of captivity but had to work out the order in which to use them to complete the challenge and get an inaccessible treat. The animal was later released.

In another astonishing test set up by BBC Two, a crow called 007 completed an eight stage puzzle in two and a half minutes.